Computing gun sight



@atfiiifi Um E. J. MIKOL COMPUTING GUN SIGHT Feb. 26, 1957 3 Sheets-Sheet 1 Filed March 31, 1953 INVENTOR. DH 4P0 J. /l //KOL BY '9. 88. WW

Feb. 26, 1957 E. J. MIKOL COMPUTING GUN SIGHT 3 Sheets-Sheet 2 Filed March 31, 1953 IN VEN TOR ion A00 J. M/mk Feb. 26, 1957 E. J. MIKOL 2,782,988

' COMPUTING GUN SIGHT Filed March 31, 1953 3 Shee'ts-Sheet 3 fpl MPD M/A OL BY 19. (4). WV

IN V EN TOR.

CQMPUTENG GUN SKGHT Edward J. Mikel, Hollywood, tjniif.

Application March 31, 1953, Serial No. 345,795

3 Claims. (Cl. 235-4515) This invention relates to a gun aiming device and, more particularly, relates to an automatically computing gun sight apparatus with mechanical, electrical and optical means for angularly deflecting the line of sight from the line of fire according to precalculated angular deflections required to achieve ultimate coincidence of a fired projectile with its intended target. This application is a continuation-in-part of my co-pending application Serial No. 196,877, filed November 21, 1950, now abandoned.

The present invention is primarily, though not necessarily, intended for use in aircraft or other movable carriers with turret-mounted guns or rockets or other missiles or projectiles intended to be aimed at a target moving relative to the moving carrier. There are a number of factors in aerial gunnery which cause deviation between the line of sight from the gun to the target and the line of fire of the gun, and for which compensation must be made in aiming the gun to etfect coincidence of the projectile and the target. Such factors are all related to the fact that a period of time elapses from the instant the projectile is fired until it arrives at the location of the target. If a projectiles velocity were so great that the velocities of the target and the carrier could be considered relatively insignificant for gunnery purposes, then the line of sight and the line of fire could be the same and the gun could be directed precisely at the target at the time of firing the projectile. To the extent that such projectile speed is not obtainable, however, and to the extent that aircraft speeds are being continually increased, some compensation must be made for the change in position of the target and the operation of the various forces and ballistic factors during the flight of the projectilet The simplest method of handling this compensation is to resolve all of the velocity components of the line of fire into vertical and horizontal components, as in a system of Cartesian coordinates, which will hereafter be called elevational and azimuthal components. Those angles which are related to the elevational and azimuthal components will be called elevational and azimuthal defiections, and will be considered to be measured between the line of sight and the line of fire.

Before describing my invention and the manner in which it achieves the proper elevational and azimuthal deflections, it will be helpful to consider briefly some of those factors which give rise to the various velocity components of the line of fire.

Considering the carrier as a still body and the target as a body moving in an azimuthal plane therewith and at an angle thereto, the line of fire must be relatively forward of the target so that the projectile will coincide with the target when the projectile has traversed the distance (hereafter called range) involved. The composite deflection angle between the line of sight from the gun to the target and the line of fire will depend upon the relative velocities of the projectile and the target and the angle of motion of the target with respect to 2,782,988 Patented Feb. 26, 1957 the carrier, since the target will traverse a certain distance during the flight of the projectile; the greater the velocity of the target and/or the greater the angle of motion of the target with respect to the carrier, the greater the amount of deflection that is required to achieve coincidence of the projectile and the target.

Considering the target as a still body and the carrier as a body moving in an azimuthal plane therewith and at an angle thereto, a velocity is imparted to the projectile due to the inertia of movement in the direction of the carriers movement, and the deflection angle must be directed backward from the direction of movement of the carrier, the amount of deflection being determined by the relative velocities of the projectile and the carrier and the angle of motion of the carrier with respect to the target.

Although both of the above examples of gunnery conditions have assumed that the carrier and the target were in an azimuthal plane, the same calculations are necessary if they are in the same elevational plane, all of the above calculations being virtually independent of the relation of the carrier and the target with respect to the ground. However, the deflection calculations based on relative motion of the target and the carrier are divided into their azimuthal and elevational components for ease in handling because of other calculations, such as the effect of the force of gravity, which require strictly elevational components. Considering both the target and the carrier as still bodies, the projectile will be deflected by the force of gravity with an acceleration downward, that velocity depending upon the time of travel of the projectile, thereby requiring an upward angular deflection ot' the line of fire from the line of sight.

All of these main gunnery and ballistic factors and others have been a major problem in the art, since great advantages would flow from the provision of an automatically compensating device capable of deviating the line of fire from the line of sight the proper amount for varying factors, and performing this function virtually instantaneously, so that the gunner may place his sights precisely on the target and fire the projectile the instant his sights are on the target. There have been numerous attempts to solve the problem; all of such attempts failing in various vital aspects. For example, many devices require tracking of the target, which means that there is a delay from the time the gunner has the sights on the target until the time the line of fire is deflected the proper angular amount from the line of sight. Other devices are applicable only when the target is maintaining a pursuit curve, that is, at any given instant of time, the target is moving in a direction pointed directly at the carrier (or slightly in front thereof); these latter devices have another inherent defect in that the cone of fire is within relat ely narrow limits of azimuthal and elevational deflection due to inherent inaccuracies beyond those limits. It is believed that there are other complicated devices which perform most of the functions required, but they necessitate use of great quantities of electronic computers and detection devices which have the disadvantages of excessive Weight and size, ditficulties of maintenance, critical adjustments, unreliability under combat conditions of gunner panic and so forth.

Generally speaking, an illustrative preferred form of the present invention comprises means responsive and related to the elevational and azimuthal components of the angles of motion and the positions of the carrier and a target with respect to each other and the ground (in re gravity elfects), electrical means responsive to the above means and to the velocities of the carrier and a target, and/or to the range, for producing corresponding electrical values, and means for vectorially adding the electrical values to produce a composite resultant elec- 3 trical value proportionate to the resultant of the elevational and azimuthal deflections for deflecting the line of sight relative to the line of fire.

In one preferred form of the present invention, cam means are provided with shapes that are precalculated to correspond to the elevational and azimuthal components of the angles of motion and the positions of the carrier and a target with respect to each other through 360 degrees of elevational and azimuthal rotation of the gun sight through a sphere of fire. The preferred form of the present invention also includes cam follower means cooperably arranged with respect to the cam means whereby eccentric movement of the cam means is trans formed into rotational movement of the cam follower means. In the preferred form of the invention, the rotational movement of the cam follower means is trans mitted to electrical means for producing corresponding electrical values of correct polarity, the latter being modified by other variable means responsive to the velocities of the carrier and a target and to the range. In one preferred general form of the present invention, the means for vectorially adding the electrical values is a cathode ray tube means responsive to the electrical values for producing a visually observable aiming spot which will be deflected from a normal position by an amount proportionate to the proper angular deflection of the line of sight relative to the line of fire.

From the above general description of the present invention, it will be obvious that the above-mentioned disadvantages of prior art computing gun sight devices are virtually completely overcome in and through the use of this invention.

With the above points in mind, it is an object of this invention to provide an improved, easily operated and maintained, compact, comparatively simple, computing gun sight for deflecting the line of sight relative to the line of fire by an angular amount which accounts for virtually all of the factors involved in achieving coincidence of a projectile, fired from a moving carrier, and a moving target.

Other and allied objects will be apparent to those skilled in the art from a carful study of the illustrations, specification and appended claims.

To facilitate understanding of my invention and the various factors for which eomoensation is made, reference will be made to the following drawings, in which:

Fig. 1 is an elevational perspective view of one preferred embodiment of the invention with some of the members thereof being partly or completely hidden by other members and, therefore, shown by broken lines.

Figure 2 is a vector diagram illustrating the computations necessary to determine the deflection angles required when the target is considered as a still body and the carrier is considered as a moving body in an elevational and/or azimuthal plane, neglecting all the other factors for these computations.

Figure 3 is a vector diagram illustrating the computations necessary to determine the deflection angles required when the carrier is considered as a still body and the target is considered as a moving body in an elevational or azimuthal plane, neglecting all the other factors for these computations.

Figure 4 is a vector diagram illustrating the computations necessary to determine the elevational deflection angles required to compensate for the effect of gravity upon a fired projectile.

Figure 5 is an electrical schematic drawing of one preferred variable potentiometer system responsive to the various deviation factors for producing coordinate electrical values corresponding thereto and algebraically adding such electrical values for application to the electron beam deflection plates of a cathode ray tube.

In Fig. 1, there is shown a movable sighting member box 11 provided with a slidably removable drawer 12.

Secured to the top of the drawer 12 is a viewing glass 13 through which a gunner observes a target. Immovably positioned relative to the viewing glass 13 and in the sighting member box 11 is a cathode ray tube 14 and a set of colliminating lenses 15 whereby an electron beam spot from the cathode ray tube 14 is projected to the viewing glass 13 as a visually observable aiming spot 16 focused at infinity so there is no parallax when the gunner moves his head. The drawer 12, together with the cathode ray tube 14, the lenses 15, the viewing glass 13 and all other electrical and mechanical associated parts (not shown), may be removed in case of failure of the cathode ray tube or any other component and a new drawer inserted in its place without disturbing the remainder of the computing gun sight apparatus, the drawer replacement having the necessary adjustments made preliminary to flight of the carrier so that replacement can be made during combat conditions.

The movable sighting member box 11 is rotatably mounted on an elevational axle 17 which is in turn rotatably mounted by bearings 18 to a yoke 19 at right angles thereto. A notched arm 20 is secured to the elevational axle 17 and provided with an angular opening 21; a solenoid 22 is secured to the yoke 19 in vertical alignment therewith and provided with a locking member 23 for selectively operable engagement with said angular opening 21 whereby the elevational axle 17 may be selectively locked to said yoke 19 for reference positioning, such as might be necessary, for example, in the event of precession of a gyroscope, to be described hereinbelow. Secured to the elevational axle 17 is a gyroscope 24 (the one just referred to) so positioned that its axis is at right angles to the elevational axle 17. Said gyroscope is adapted to stabilize the axle 17, when uncaged. The sighting member box 11 also contains an elevational selsyn which is electrically connected to a gun-turret selsyn (not shown) that controls the elevational movement of the guns (not shown) relative to the gun sight, the body and stator windings 25 of said elevational selsyn being immovably positioned relative to said sighting member box 11 and rotatable relative to its rotor 26 which is immovably positioned upon the elevational axle 17.

An azimuthal axle 27 is fixed to the yoke 19 and extends at a right angle to said elevational axle 17 and into an azimuthal box 28, wherein an azimuthal selsyn which is electrically connected to a gun-turret selsyn (not shown) controls the azimuthal movement of the guns (not shown) relative to the gun sight, has its body and stator windings 29 in immovable relationship with respect to said box 28 and its rotor 30 immovably secured to said azimuthal axle 27. It should be noted that the elevational and azimuthal selsyns are so arranged that elevational rotation of the sighting member box 11 with respect to the elevational axle 17 and azimuthal rotation of the sighting member box 11 in cooperation with the azimuthal axle 27 with respect to the azimuthal box 28 result in relative rotation of the rotors and stators of the elevational and azimuthal selsyns whereby elevational and azimuthal movement of the guns may be effected.

Secured to the elevational axle 17 in immovable relation thereto are three elevational earns, the first cam 31 being the carrier elevational direction cam, the second cam 32 being the gravity elevational compensation cam, and the third cam 33 being the target dive-climb cam, adapted, together with another target dive-climb cam 62 (to be described hereinafter) to compensate for target velocity changes caused by' the target diving or climbing.

Secured to the azimuthal axle 27 in immovable relation thereto are two azimuthal cams 34 and 35, the first cam 34 being the carrier azimuthal direction cam and the second cam 35 being the azimuthal parallax compensation cam. Each of the cams has a precalculated shape corresponding to the requisite correction factor for deflection of the line of sight from the line of fire of the greases guns, such precalculations to be described in detail below. Cooperably arranged with respect to each of said cams and in liftable slidable contact therewith are cam followers 36, 37, 38, 39 and 40, respectively; each of said cam followers having one end thereof immovably mounted with respect to the corresponding rotatable shaft 41, 42, 43, 44 and 45 of the corresponding variable electrical potentiometer 46, 47, 48, 49 and 50. The three variable electrical potentiometers 46, 47 and 48 that are cooperably arranged with respect to the elevational earns 31, 32, and 33, respectively, are secured to the sighting member box 11 and may be zero-adjusted; the two variable electrical potentiometers 49 and 50 that are cooperably arranged with respect to the azimuthal cams 34 and 35, respectively, are secured to the azimuthal box 28 and may be zero-adjusted. It should be noted that, in operation, elevational and azimuthal rotation of the sighting member box 11 will cause relative movement of the cams and the corresponding cam followers, which will cause the elevational and azimuthal cam followers, respectively, to ride on different portions of their corresponding cams, and the resulting lift movements of the cam followers will cause relative rotation of the rotatable shafts of each of the variable electrical potentiometers with respect to the respective potentiometer.

A target attitude indicator 51 is positioned near the viewing glass 13 so that the operator of the gun sight may see the target attitude indicator 51, the aiming spot 16 on the viewing glass 13 and the target at the same time. Said target attitude indicator 51 may be in the shape of an aircraft or its fuselage only, or in the shape of any other likely target, and is manually positionally adjustable into an attitude simulating the direction of flight of a target by means of elevational and azimuthal gears. Said target attitude indicator 51 is mounted on a ball and socket 52 at the end of an azimuthal shaft 53 which is rotatably mounted, by arms 101 and 102, with respect to the sighting member box 11 and provided with an azimuthal target attitude gear 54 and an azimuthal target attitude cam 55 immovably mounted on said azimuthal shaft 53. Movably engaged with said azimuthal target attitude gear 54 and at a right angle thereto is an azimuthal target attitude control gear 56 secured to a shaft 57 which is mounted to a rotatable handle 58 whereby rotation of said handle 58 will cause rotation of the azimuthal target attitude control gear 56 which will cause rotation of the azimuthal target attitude gear 54 which will cause rotation of both the azimuthal target attitude cam 55 and the target attitude indicator 51 in an azimuthal manner. The target attitude indicator 51 is cooperably engaged by an elevational shaft 59 at a right angle relative to the azimuthal shaft 53 at the ball and socket 52 whereby the target attitude indicator 51 may be tilted to the desired elevational angle simulating the attitude of the target. Said elevational shaft 59 is provided with an elevational target attitude gear 60 and two cams immovably positioned on said elevational shaft 59, the first cam 61 being an elevational target attitude cam and the second cam 62 being a target dive-climb cam. Movably engaged with said elevational target attitude gear 60 and at a right angle thereto is an elevational target attitude control gear 63 in the form of a rectilinear track gear or rack. Said elevational target attitude control gear 63 is slidably longitudinally engaged with respect to arm 103 and slidably engaged at an angle to a wheel 64 which is slidably engaged with the shaft 57 and provided with a trigger-like extending arm 65 which is capable of being engaged by a finger of a hand grasping the handle 58. Said arm 65 is biased away from the handle 58 by a biasing spring 66 which is set into the handle 58. It should here be noted that an operator of the gun sight may, with one hand, position the target attitude indicator 51 in an azimuthal position by rotating the handle 58 and in an elevational position by pulling or releasing the extending arm 65, in each case rotating the azimuthal target attitude cam 55, and the elevational target attitude cam 61 and target dive-climb cam 62, respectively, each with respect to its axis. Each of said cams 55, 61 and 62 has a precalculated shape corresponding to the requisite correction factor for deflection of the line of sight from the line of fire of the guns, such precalculations to be described in detail below. Cooperably arranged with respect to the azimuthal target attitude cam 55, the elevational target attitude cam 61 and the target dive-climb cam 62 and in li'fta'ble slidable contact therewith are target attitude cam followers 67, 68 and 69, respectively, each of said cam followers having one end thereof immovably mounted with respect to the rotatable shaft of a variable electrical potentiometer 70, 71 and 72, respectively, whereby rotation of said target attiude cams 55, 61 and 62 causing lifting movement of said target attitude cam followers 67, 68 and 69 results in relative rotation of the rotatable shafts of each of the variable electrical potentiometers 70, 71 and 72 with respect to its respective potentiometer. The target attitude indicator may be spring loaded to return to an attitude simulating that of a target following a pursuit curve with respect to the carrier, thus eliminating the necessity of manual operation of the target attitude indicator when the gunner suiiers from panic due to being under fire from the target.

Located on the azimuthal box 28 are three manually selectively rotatable knobs 73, 74 and 75, the first of said knobs 73 being the manual carrier velocity control, the second 74 being the manual target velocity control and the third 75 being the manual range control for the parallax and gravity compensations. Each of these controls will be described later.

A target dive-climb switch 76 is also located on the azimuthal box 28 for on-off positioning whereby the compensation offered by the target dive-climb cams 62 and 33 and their associated electrical circuits may be selectively operative or inoperative depending upon whether analogue target velocity voltages are used (to be discussed later).

An electrical plug outlet 77 is also located on the azimuthal box 28 for insertion of the voltages and elec trical connections required. A flexible electrical conduit 78 extends from the azimuthal box 28 to the sighting member box 11 whereby the proper voltages are supplied and electrical connections are made.

In Fig. 2, there is shown a vector construction diagram in which the elevational or azimuthal deflection angles are calculated in either an elevational or azimuthal plane when the target T is considered as a still body and the carrier C is considered as a moving body. The velocity of the projectile, considered by itself, is assumed to be 1000 yards per second (the velocity units will hereafter be abbreviated as Y. P. S.), the velocity of the carrier C is assumed to be 300 Y. P. S., and the direction from C to T is considered as the 0 degree carrier direction angle relative to the target T, the carrier direction angle increasing in a clockwise direction for 360 degrees in carrier azimuthal or elevational direction. The range (the distance from the carrier C, at its initial position at the time of firing, to the target T) may be any value but is here shown to be 1000 yards, the distance corresponding to the distance the projectile will travel in one second, neglecting the effect of carrier velocity; it should be made clear that the range has no effect on the deflection angles necessary to compensate for carrier movement. All of the vector values shown and hereinafter described are velocity vectors, and all of the circles and arcs shown and hereinafter described are lines through the terminal points of an infinite number of vectors. In referring to any particular vector value, the designation will be to the vector line. All velocities are assumed to be constant, the efiective validity of this assumption being pointed out later.

greases Although the mathematical function of the deflection angles as related to the carrier direction angles can be reduced to a mathematical formula, it is deemed advisable to describe two specific calculations for the purpose of explaining the nature of the compensation factors involved. Assuming the carrier C to be moving at a carrier direction angle of 30 degrees relative to the target T, a carrier velocity vector A is drawn to the carrier velocity circle B at a 30 degree angle to the line CT, the length of said vector A being representative of the carrier velocity of 300 Y. P. S. (as is the radius of the carrier velocity circle B). The vector A also represents the velocity that will be imparted to the projectile, at the time of firing, by the movement of the carrier C. The are D is part of the projectile velocity circle, being the line through the terminal points of an infinite number of velocity vectors represent ing the muzzle velocity of the projectile due to its own propulsion. Since the target T remains stationary, and the projectile is fired from the carrier C at the carriers initial position at C, the desired flight path of the projectile must be along the line CT, and hence the resultant of the projectile velocity vector along the line of fire and the carrier velocity vector A must be in the direction of the line of sight, the line CT from the carrier C to the target T. Resolving the carrier velocity vector A into two components, the first component in the resultant direction CT and the second component at a right angle thereto, the projectile velocity vector along the line of fire E must have a component equal in quantity and opposite in direction to the said second component of the carrier velocity vector A. A line F is drawn parallel to the line of sight CT and at a distance therefrom equal to the said second component of the carrier velocity vector A; the intersection of the line F with the projectile velocity are D is the terminal point of the projectile velocity vector E, said vector E now being drawn. In effect, the projectile velocity vector E is the resultant of the two velocity componcnts, one in the direction of the target T and the other equal in quantity and opposite in direction to the second component of the carrier velocity vector A. If the line of fire (the direction the guns are pointed) is in the direction of the projectile velocity vector E, the projectiles path will be from C to T, the line of sight, with a resultant velocity of the vectorial sum of the carriers velocity and the projectilcs velocity due to its own propulsion.

The angle G between the line of fire E and the line of sight CT is the proper deflection angle to achieve coincidence of the projectile and the target when the carrier C is moving at a 30 degree angle relative to the target at the time of firing. The angle G is about 8.3 degrees under the assumed conditions. Assuming the carrier C to be moving at a carrier direction angle of 90 degrees relative to the target T, the calculations may be made in the same manner with a resulting deflection angle H of about l7.7 degrees. Decreasing velocity of the projectile due to air resistance will have virtually no effect since the component velocities will decrease proportionately and the projectile will follow the same path. The range will have no effect on these calculations since the projectile will be traveling a straight path from the carrier C to the target T, the calculations being independent of range. The deflection angle will vary with variations in carrier velocity, the compensation therefor being considered later in connection with the electrical circuit: the deflection angle also will vary for variations in initial projectile velocity, and this may also be compensated for in the same general manner, if desired.

The carrier elevational direction cam 31 and the can rier azimuthal direction cam 34 are shaped in accordance with the above calculations to provide litt movement of the cam followers 36 and 39, respectively, whereby the resistances of the variable electrical potentiometer-S 46 and 49, respectively, are varied in accordance with the shape of the said carrier direction cams 31 and 34. The effect of this electrical resistance variation upon the deflection of the line of sight from the line of fire will be explained later.

In Fig. 3, there is shown a vector construction diagram in which the azimuthal or elevational deflection angles are calculated in either an azimuthal or elevational plane when the carrier C is considered as a still body and the target T' is considered as a moving body. The velocity of the projectile is assumed to be 1000 Y. P. S., the velocity of the target T is assumed to be 300 Y. P. S., and the direction from T to C to be considered as the 0 degree target attitude azimuthal angle relative to the carrier C, the target attitude azimuthal angle increasing in a clockwise direction for 360 degrees in target azimuthal direction. The range (the distance from the carrier C to the target T at its initial position at the time of firing) may be any value but is here assumed to be 1000 yards, corresponding to the distance the projectile will travel in one second; it should be made clear that the range has virtually no practical eflect on the ensuing calculations. All of the vector values shown and hereinafter described are velocity vectors, and all of the circles and arcs shown and hereinafter described are lines through the terminal points of an infinite number of vectors, unless indicated otherwise. In referring to any particular vector value, the designation will be made to the vector line. All velocities are assumed to be constant.

As in the case of the moving carrier and still target calculations, the mathematical function of the deflection angles as related to the target attitude angles can be reduced to a mathematical formula, but it is again deemed advisable to describe specific calculations for the purpose of explaining the nature of the compensation factors involved. The calculations will be described for the target attitude azimuthal angles; the calculations are the same for the target attitude elevational angles except that the azimuthal plane must be tipped degrees about an axis through the azimuthal plane and at a right angle to the line of sight between the carrier C and the target T, and the numerical degree values rotated 90 degrees clockwise in the new elevational plane. Assuming the target T to be moving at a given target attitude angle relative to the carrier C, the target velocity component at a right angle to the line T'C is known; the projectile velocity must have the same component in order for the projectile to be moving at a proper deflection angle. Therefore, the sine of the deflection angle must be the ratio of the target velocity right angle component to the projectile velocity. In the case of a 30 degree target attitude angle 1, the projectile must have a velocity component of Y. P. S. at a right angle to the line of sight CT, the proper deflection angle K being about 8.65 degrees under the assumed conditions. The deflection angle K is found by drawing the target velocity vector L at the target attitude angle J to the target velocity circle M, then projecting the construction line N parallel to the line of sight C' until it intersects the projectile velocity are P; a line of fire line Q is then drawn from that intersection to the carrier C, defining the deflection angle K between the line of fire Q and the line of sight CT. If the range is 1000 yards as shown, the projectile will coincide with the target at the intersection of the target velocity vector L and the line of fire Q, considering those vectors as distance rather than velocity with their length corresponding to distance. The same procedure may be followed with a 90 degree target attitude angle, the proper deflection angle R then being about 17.45 degrees. A coincidence circle S may be drawn through the intersections of an infinite number of target velocity vectors and projectile velocity vectors corresponding to the distances at which the projectile will coincide with the target at an initial range of 1000 yards and the other conditions as assumed. For target attitude elevational angles, the target velocity circle must 9 be rotated 90 degrees about the 90-degree-270-degree' line shown and then the numerical degree values must be rotated 90 degrees about the line of sight C'- Decreasing velocity of the projectile due to air resistance will have little effect but compensation may be made by increasing the angles of deflection the proper amount, which may be done by using average projectile velocity in drawing the projectile velocity are P. The range will have little or no appreciable effect on these calculations.

The azimuthal target attitude cam 55 and the elevational target attitude cam 61 are shaped in accordance with the above calculations to provide lift movement of the cam followers 67 and 68, respectively, whereby the resistances of the variable electrical potentiometers 70 and 71, respectively, are varied in accordance with the shape of the said target attitude cams 55 and 61. The effect of this electrical resistance variation upon the deflection of the line of sight from the line of fire will be explained later.

In Fig. 4, there is shown a construction diagram in which the elevational deflection angles to compensate for the effect of gravity are calculated in an elevational plane when both the carrier C and the target T" are considered as still bodies. The acceleration due to gravity is approximately 10.73 yards per second per second downward, which value will hereinafter be called g; the vertical distance the projectile will drop due to the effect of gravity during a period of time t is /zgt All of the vectors shown are distance vectors. If a projectile is fired from the carrier C" at a target T at a horizontal range of 1000 yards with a projectile velocity of 1000 Y. P. S., the projectile will drop a distance of about 5.37 yards in the elapsed time of one second, requiring the line of fire U to be deflected upward from the line of sight V by a deflection angle W of about 0.31 degree. The line of sight in that case will be considered degrees in elevation, the angle increasing in a clockwise direction for 360 degrees in gravity elevational angle. At 90 degrees and 270 degrees, the correction factor will be zero, with continuously varying factors thereinbetween. The gravity elevational compensation cam 32 is shaped in accordance with the above calculations to provide lift movement of the cam follower 37 whereby the resistance of the variable electric potentiometer 47 is varied in accordance with the shape of the said gravity elevational compensation cam 32. The effect of this electrical resistance variation upon the deflection of the line of sight from the line of fire will be explained later, as will the manner of compensating for different ranges.

Not shown in the drawings, because of the simplicity of the concept in view of the above descriptions, are the calculations for parallax-compensations which are required when the position of the gun is displaced from the position of the gun sight. Naturally, the shorter the range from the carrier to the target, the greater the parallax angle compensation necessary in order for the line of fire to converge upon the line of sight at the target. Also, the compensation depends upon the target position relative to the carrier, since no azimuthal parallax correction is necessary when the gun sight and the gun are aligned along the longitudinal axis of the carrier in the direction of the target. The parallax compensation cam 35 is shaped in accordance with the requisite correction factor corresponding to the target position relative to the carrier to provide lift movement of the cam follower 40, whereby the variable electrical potentiometer 50 is varied in accordance with the shape of said parallax compensation cam 35. The effect of this electrical variation upon the deflection of the line of sight from the line of fire will be explained later, as will the manner of compensating for different ranges.

In Fig. 5, there is shown a schematic diagram of the electrical circuit, with the electrical equivalents of those members shown in Fig. 1 having the same numeral desinbefore taught.

en ages '10 ignations, primed however. Deflection voltages are ap plied to the cathode ray tubes azimuthal and elevational deflection plates 79 and 80, respectively; the direct current voltage source entering the potentiometer network at positive and negative terminals 81 and 82, respectively, the potentiometer network varying the applied deflection voltages in accordance with the algebraic addition of the varying voltages due to the variations in the potentiometers which are varied in response to the required deflection components to properly deflect the line of sight from the line of fire in the various manners here- The voltage fed into the carrier azimuthal direction potentiometer 49 may be selectively varied by the variable potentiometer 83 which is manually selectively adjustable in accordance with the carrier velocity by the control knob 73, in Fig. l. in mechanically ganged connection with said potentiometer 83 is the variable potentiometer 84 which selectively varies the voltage fed into the carrier elevational direction potentiometer 46' in the same manner. The voltage fed into the target azimuthal direction potentiometer 70' may be selectively varied by the variable potentiometer 85 which is manually selectively adjustable in accordance with estimated target velocity by the control knob 74, in Fig. 1, such adjustment being based on the operators identification of the type of target and knowledge of its usual combat speed. In mechanically ganged connection with said potentiometer 85 is the variable potentiometer 86 which selectively varies the voltage fed into the target elevational direction potentiometer 71' in the same manner. The target dive-climb potentiometers 72' and 48 operate as an auxiliary target velocity compensator to give continuously changing deflection voltages corresponding to a diving or climbing targets increase or decrease in velocity from the estimated straight level target speed, thereby eliminating the necessity of changing the setting of the variable potentiometers 85 and 86 during firing of the guns. A manual switch 76' operates to make the target dive-climb compensation available only when the gunner is using the manual target velocity controls, and is thrown to the off position when analogue velocity voltages are used. Instead of being a different unit of the circuit, the target dive-climb velocity compensation voltage may be fed directly into the target elevational direction potentiometer 71 for modifying the voltage therein accordingly,

a switch similar to switch 76' still being available for selective operation. The voltages fed into the azimuthal parallax compensation potentiometer 50 and the gravity elevational compensation potentiometer 47, respectively, may be selectively varied by the variable potentiometers 87 and 88, respectively, which are manually selectively adjustable in accordance with the rangeby the control knob 75, in Fig. 1, and may be mechanically gang connected directly or through appropriate compensating linkages. Where extreme variations in range are expected, such compensation may also be provided for potentiometers 70 and/ or 71' and/or 72. The resistive values of the electrical circuit components are so chosen that variations in one unit circuit have virtually no effect upon the other unit circuits.

Instead of manually adjusting the various velocity and range potentiometers to compensate for the above-mentioned factors, external analogue voltages may be fed into the circuits at the appropriate points which will automatically compensate for variations in carrier and target velocity and range. For example, an external voltage from the carriers air speed indicator (corrected to indicate true carrier speed with respect to ground) may be fed into the carrier direction compensation circuits at points 89 and 90; an external voltage from a radar or similar device which determines velocity of the target may be fed into the target direction compensation circuits at points 91 and 92; and an external voltage from a ranging radar device may be fed into the parallax compensation and gravity compensation circuits at points 93 and 94, respectively.

Elevational parallax correction means is not shown, but would be virtually identical to the azimuthal parallax correction means described and illustrated. Such elevational parallax correction means may be included, if desired.

The combined elfect of all the deflection voltages upon an electron beam in the cathode ray tube is the deflection of that beam from the norm position in a manner which is proportionate to the combination of all the deflection angles previously calculated for any one position of the gun sight and the target attitude indicator, all of which are appropriately electrically modified by velocity and range factors. Therefore, the operator of the computing gun sight has merely to position the sighting member box 11 in an elevational and azimuthal manner so that the aiming spot 16 is on the target in order to deviate the line of fire the proper amount to achieve ultimate coincidence of a fired projectile and the target. Virtually all of the deflection components between the line of sight and the line of fire have been taken into account without the necessity of leading the line of sight from the target. If desired, any additional predictable variable factors can be precalculated and the same or additional cams can be shaped in accordance therewith.

It should be noted that the example described and illustrated herein is illustrative only and numerous modifications within the scope of the present invention will occur to those skilled in the art and all such are intended to be included and comprehended herein. For example, elevational and/ or azimuthal gyroscopes, either selectively caged or uncaged or used with sensing means, may be added to the sighting member box 11 and/or the azimuthal axle 27 to give stability to the device during operation thereof, the stabilizing force of said gyroscopes being easily overcome by the gunner for rotation of the sighting member box 11. The relative movement of the cams and the potentiometers may be obtained by having either one of them movable and the other stationary, the principle being relative movement with respect to each other so that the potentiometer is varied in deflection voltage output. While the present invention has been described in connection with an aiming spot provided by a cathode ray tube, any means for providing a deflected aiming means, whereby the line of sight is de ilected from the line of fire in accordance with the dellection voltages, may be employed, such as electrically operated reticle lines deflected in elevational and azimuthal relation to a norm position. The cams and cam followers can be arranged in numerous cooperable relationships within the spirit of relative movement, it not being necessary that the cam followers ride on the outside of the cams. The cams may be internally shaped or grooved, and the cam followers may ride on the internal surface of the cams or in grooves, being positively maintained therein.

The embodiments described and illustrated herein are exemplary only, and are not intended to limit the scope of the present invention, which is to be interpreted in the light of the prior art and the appended claims only, with due consideration for the doctrine of equivalents.

I claim:

1. A gun aiming device wherein at least one gun, which is movably mounted on a movable carrier, is caused to be aimed along a line of fire deviated from a line of sight, at a movable target, whereby to elfectively compensate for factors affecting the ultimate coincidence of a fired projectile and said target, comprising: a movable sighting member; a movable gun member; means responsive to several factors including the position and direction of movement of a carrier with respect to a target,

considered as a still body, when said sighting member is aimed at said target, and responsive to the velocity of movement of said carrier, for producing corresponding electrical values related to said factors; means responsive to several additional factors including the direction of movement and the velocity of movement of a target with respect to the carrier, considered as a still body, for producing a second set of corresponding electrical values related to said additional factors; means responsive to the elevational position of a target with respect to the carrier, when said sighting means is aimed at said target, for producing a corresponding electrical value related thereto to provide compensation for the effect of gravity on a fired projectile; means for algebraically adding said electrical values which are proportionate to the required deviation components of the line of fire and the line of sight to produce other coordinate electrical values proportionate to the Cartesian coordinates of a total deviation electrical value; said movable sighting member including cathode ray tube means responsive to said coordinate electrical values for producing a visually observable aiming spot deflected from a norm position by the appropriate deviation whereby to produce a proper deviation of the line of sight and the line of fire; said means responsive to the position and direction of movement of the carrier with respect to a target, considered as a still body, comprising cam means having precalculated shapes corresponding to the requisite correction factors, cam follower means cooperably arranged with respect to the cam means, and variable electrical means operable in response to relative movement of the cam follower means to effectively produce corresponding electrical values related to said corrective factors, said cam means and said cam follower means being relatively movable in response to relative movement of the sighting member and the gun member with respect to a predetermined reference position; said means responsive to direction of movement of a target with respect to the carrier, considered as a still body, comprising a second set of cam means having precalculated shapes corresponding to the requisite correction factors, a second set of cam follower means cooperably arranged with respect to the second set of cam means, and second variable electrical means operable in response to relative movement of the second cam follower means to eflFectively produce corresponding electrical values related to said corrective factors, and manually positionally adjustable target simulating means capable of being adjusted to an attitude simulating that of a target, said cam means of said second set and said cam follower means of said second set being relatively movable in response to movement of said target simulating means with respect to a predetermined reference position; said means responsive to the elevational position of a target with respect to the carrier comprising third cam means having a precalculated shape corresponding to the requisite correction factor, third cam follower means cooperably arranged with respect to said third cam means, and a third variable electrical means operable in response to relative movement of the third cam follower means to effectively produce a corresponding electrical value related to said corrective factor, said third cam means and said third cam follower means being relatively movable in response to relative elevational movement of the sighting member and the gun member with respect to a predetermined reference position.

2. A gun aiming device wherein at least one gun, which is movably mounted on a movable carrier, is caused to be aimed along a line of fire deviated from a line of sight, at a movable target, whereby to effectively compensate for factors affecting the ultimate coincidence of a fired projectile and said target, comprising: a movable sighting member; a movable gun member; means responsive to several factors including the position and direction of movement of a carrier with respect to a target, considered as a still body, when said sighting member is aimed at said target, and responsive to the velocity of movement of said carrier, for producing corresponding synapse electrical values related to said factors; means responsive to several additional factors including the direction of movement and the velocity of movement of a target with respect to the carrier, considered as a still body, for producing a second set of corresponding electrical values related to said additional factors; means responsive to the elevational position of a target with respect to the carrier, when said sighting means is aimed at said target, for producing a corresponding electrical value related thereto to provide compensation for the effect of gravity on a fired projectile; means for algebraically adding said electrical values which are proportionate to the required deviation components of the line of fire and the line of sight to produce other coordinate electrical values proportionate to the Cartesian coordinates of a total devia-- tion electrical value; said movable sighting member including cathode ray tube means responsive to said coordinate electrical values for producing a visually observable aiming spot deflected from a norm position by the appropriate deviation whereby to produce a proper deviation of the line of sight and the line of fire; said means responsive to the position and direction of movement of the carrier with respect to a target, considered as a still body, comprising cam means having precalculated shapes corresponding to the requisite correction factors, cam follower means cooperably arranged with respect to the cam means, and variable electrical means operable in response to relative movement of the cam follower means to effectively produce corresponding electrical values related to said corrective factors, said cam means and said cam follower means being relatively movable in response to relative movement of the sighting member and the gun member with respect to a predetermined reference position; said means responsive to direction of movement of a target with respect to the carrier, considered as a still body, comprising a second set of cam means having precalculated shapes corresponding to the requisite correction factors, a second set of cam follower means cooperably arranged with respect to the second set of cam means, and second variable electrical means operable in response to relative movement of the second cam follower means to effectively produce corresponding electrical values related to said corrective factors, and manually positionally adjustable target simulating means capable of being adjusted to an attitude simulating that of a target, said cam means of said second set and said cam follower means of said second set being relatively movable in response to movement of said target simulating means with respect to a predetermined reference position; said means responsive to the elevational position of a target with respect to the carrier compris ing third cam means having a precalculated shape corresponding to the requisite correction factor, third cam follower means cooperably arranged with respect to said third cam means, and a third variable electrical means operable in response to relative movement of the third cam follower means to effectively produce a corresponding electrical value related to said corrective factor, said third cam means and said third cam follower means being relatively movable in response to relative elevational movement of the sighting member and the gun member with respect to a predetermined reference position; said means responsive to carrier velocity comprising selectively adjustable electrical value modifying means cooperable to modify the electrical values in response to the effect of said velocity on the ultimate coincidence of a fired projectile and a target; said means responsive to target velocity comprising selectively adjustable electrical value modifying means cooperable to modify the electrical values in response to the effect of said velocity on the ultimate coincidence of a fired projectile and a moving target.

3. A gun aiming device wherein at least one gun, which is movably mounted on a movable carrier, is caused to 14 be aimed along a line of fire deviated from a line of sight, at a movable target, whereby to effectively compensate for factors affecting the ultimate coincidence of a fired projectile and said target, comprising: a movable sighting member; a movable gun member; means responsive to several factors including the position and direction of movement of a carrier with respect to a target, considered as a still body, when said sighting member is aimed at said target, and responsive to the velocity of movement of said carrier, for producing corresponding electrical values related to said factors; means responsive to several additional factors including the direction of movement and the velocity of movement of a target with respect to the carrier, considered as a still body, for producing a second set of corresponding electrical values related to said additional factors; means responsive to the elevational position of a target with respect to the carrier, when said sighting means is aimed at said target, for producing a corresponding electrical value related thereto to provide compensation for the effectof gravity on a fired projectile; means for algebraically adding said electrical values which are proportionate to the required deviation components of the line of tire and the line of sight to produce other coordinate electrical values proportionate to the Cartesian coordinates of a total deviation electrical value; said movable sighting member including cathode ray tube means responsive to said coordinate electrical values for producing a visually observable aiming spot deflected from a norm position by the appropriate deviation whereby to produce a proper deviation of the line of sight and the line of fire; said means responsive to the position and direction of movement of the carrier with respect to a target, considered as a still body, comprising cam means having precalculated shapes corresponding to the requisite correction factors, cam follower means cooperably arranged with respect to the cam means, and variable electrical means operable in response to relative movement of the cam follower means to effectively produce corresponding electrical values related to said corrective factors, said cam means and said cam follower means being relatively movable in response to relative movement of the sighting member and the gun member with respect to a predetermined reference position; said means responsive to direction of movement of a target with respect to the carrier, considered as a still body, comprising a second set of cam means having precalculated shapes corresponding to the requisite correction factors, a second set of cam follower means cooperably arranged with respect to the second set of cam means, and second variable electrical means operable in response to relative movement of the second cam follower means to effectively produce corresponding electrical values related to said corrective factors, and manually positionally adjustable target simulating means capable of being adjusted to an attitude simulating that of a target, said cam means of said second set and said .cam follower means of said second set being relatively movable in response to movement of said target simulating means with respect to a predetermined reference position; said means responsive to the elevational position of a target with respect to the carrier comprising third cam means having a precalculated shape corresponding to the requisite correction factor, third cam follower means cooperably arranged with respect to said third cam means, and a third variable electrical means operable in response to relative movement of the third cam follower means to effectively produce a correspondingelectrical value related to said corrective factor, said third cam means and said third cam follower means being relatively movable in response to relative elevational movement of the sighting member and the gun member with respect to a predetermined reference position; said means responsive to carrier velocity comprising selectively adjustable electrical value modifying means cooperable to modify the electrical values in 16 response to the effect of said velocity on the ultimate cotrieal values in response to the effect of range on the ultiincidence of a fired projectile and a target; said means mate coincidence of a fired projectile and a moving target. responsive to target velocity comprising selectively adjustable electrical value modifying means cooperable to References Cited in the file of this Patent modify the electrical values in response to the effect of 5 UNITED STATES PATENTS said velocity on the ultimate coincidence of a fired projectile and a moving target; and means correlatable with g gggg respect to the range from the carrier to a target and rey sponsive to said range for eifectively modifying the elec- 2658674 Darlmgion et a1 1953 

